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Pine needles decompose very
Pine needles decompose very slowly, even when shredded, so don't add too much of the leaf/needle mixture to your compost pile. A better choice might be to use the shredded mixture as a weed-suppressing, water-retaining mulch in your garden.
 
 
To increase the carbon content of your compost, why not ask your neighbors if you can scrounge bags or piles of fall leaves they won't be using. Non-diseased garden debris (leaves, stems, flowers from dead plants)is another option.